WORK DONE on the refrigerant.Work done by compressor, Win = QH - QL (Heat of COMPRESSION) = h2 - H1 (Enthalpy increase in compressor)\(COP = \frac{{{Q_L}}}{{{W_{in}}}} = \frac{{{Q_L}}}{{{Q_H} - {Q_L}}} = \frac{{{h_1} - {h_4}}}{{{h_2} - {h_1}}}\)